Athletic activity is important to maintaining a healthy lifestyle and is a source of entertainment for many people. Some individuals prefer to engage in team athletic activities such as, for example, soccer or basketball, while other individuals prefer to engage in individual athletic activities such as, for example, running or skiing. Regardless of whether the activity is a team or individual activity, it is common for individuals to participate in both competitive sessions, such as a soccer match or a running race, and more informal training sessions such as conducting soccer drills or running interval sprints. Others who do not themselves regularly take part in athletic activities may nevertheless enjoy viewing athletic activities as a spectator.
Athletic activity monitoring systems exist that are capable of recording information about an individual's performance during an athletic activity using sensors. Some portable fitness monitoring systems employ sensors attached to the individual's body, while other portable fitness monitoring systems rely on sensors attached to a piece of athletic equipment. Such sensors may be capable of measuring various physical and/or physiological parameters associated with the individual's athletic activity.
Technology has resulted in the development of so-called “heads up displays” (HUDs) for presenting visual information to a user without requiring the user to look away from their usual viewpoint. The origin of the term stems from airplane pilots being able to view information (e.g. flight status or plane orientation information) with their heads still positioned “up” and looking forward, instead of angled down looking at lower instruments. HUDs typically include a projector for projecting information onto a transparent surface, such as a glass plate, that enables the background environment of the user's typical viewpoint to still be seen. Although HUDs were initially developed for military aviation, they can now be found in commercial aircraft, automobiles, and computer gaming applications.
HUDs can be a useful tool for a variety of “augmented reality” applications. The basic idea of augmented reality is to present computer-generated sensory input to a user—superimposed graphics, audio, haptic feedback, or other sensory enhancements—that provide information about the environment and its objects in the context of a real-world environment. For example, fans of American football have become accustomed in recent years to the presence a super-imposed “first-down” line on televised American football games.
An individual engaged in an athletic activity—or an interested observer such as a coach or fan—may desire to receive information about the athletic activity, including information about the individual's performance. But with respect to providing this information, existing athletic activity monitoring systems suffer from a number of drawbacks. Many existing systems do not provide the individual or interested observer with information about the athletic activity until after the activity has been completed. Other systems may present the information about the athletic activity during the activity, but in a way that distracts that individual or interested observer from focusing on the ongoing athletic activity itself. And many existing HUDs and augmented reality systems are not portable and are therefore not suitable for monitoring in many real world athletic competitive or training sessions. Finally, existing athletic activity monitoring systems often fail to provide the individual or interested observer with quick, accurate, insightful information that would enable them to easily compare past performances, develop strategies for improving future performances, or visualize performances.